The present invention relates to a vacuum processing apparatus for processing an objective, for example, a substrate-like sample such as a semiconductor wafer in a processing chamber inside a vacuum container and more particularly, to a vacuum processing apparatus having a plurality of vacuum containers (process units) provided for a transfer system unit, generally called a cluster tool, thus having the ability to process a plurality of wafers to improve the productivity.
A semiconductor production apparatus for producing a semiconductor device by processing a semiconductor wafer as above is provided with a plurality of process units each having a vacuum container with an internal processing chamber called a process unit, a vacuum evacuation unit and a plasma generation unit and is used to process a substrate-like sample such as a semiconductor wafer (hereinafter referred to as a wafer) by using a plasma generated in the processing chamber. In the semiconductor production apparatus of this type, low costs and improved productivity are demanded and especially, an important problem resides in that the number of wafers to be processed per unit time is increased to promote the efficiency of process which one apparatus can yield.
In the aforementioned semiconductor production apparatus, a cassette for storing a predetermined number of wafers, for example, 25 wafers is mounted in front of the apparatus and a robot for transfer takes out wafers one by one from the cassette and transfers it to a lock chamber and thereafter the thus extracted wafer to be applied with processing is transferred from the lock chamber, vacuum evacuated for pressure reduction, to a processing chamber inside a vacuum container of each of the process units for processing through the medium of a reduced-pressure transfer path, causing the wafer to be processed in the processing chamber. After the process ends subsequently, the wafer is again taken out so that it may be returned to the atmospheric pressure by way of the lock chamber through the medium of a path in a direction opposite to the take-in direction. Thereafter, the wafer is returned to the identical position from which it is taken out by means of the transfer robot. This is the general operation sequence of processing the wafer in the semiconductor production apparatus.
For the operation sequence, operation patterns are available including assigning a plurality of process units to one cassette, assigning one process unit to one cassette and assigning a plurality of process units to a plurality of cassettes at a time and as the case may be, a process is carried out over a plurality of process units or a process is carried out for adjusting the condition of the process unit in advance, demonstrating that there are a variety of sophisticated operation patterns.
Examples of the semiconductor production apparatus technique are known from JP-A-2006-190894 and JP-A-2007-129177.
JP-A-2006-190894 discloses a cluster tool having a plurality of processing chambers (process modules) and a transfer mechanism for interconnecting them and when the transfer mechanism delivers samples to the individual processing chambers in accordance with processes to be applied sequentially to the samples inside the plural processing chambers, an unprocessed sample is interchanged with a processed sample to thereby improve the total transfer efficiency.
JP-A-2007-129177 discloses a cluster tool having a plurality of processing chambers (process modules) and a transfer mechanism for interconnecting them and the sample transfer is not started until conditioning of all of the plural processing chambers has been completed but is started in sequence initially with a processing chamber whose conditioning has been completed, thus improving the total transfer efficiency.